I.V. flow control device

Abstract

A flow selector and regulator for use in an I.V. administration arrangement which includes the capability of establishing the flow rate without calibration at the time of use and then automatically maintaining that flow rate regardless of changes in fluid pressure in either or both of upstream or downstream of the regulator. The regulator utilizes a diaphragm which is not subject to stretching or material stress prior to use to control an orifice. The regulator is capable of being calibrated at the time of manufacturer directly in terms of flow rate, something which is not possible in prior such devices. The diaphragm is clamped at the rim and has an arcuate torus facing the inlet and a bulbous central section which controls flow through an outlet orifice. Liquid bypasses the diaphragm through the rim. Other embodiments incorporate the regulator into a drip chamber and reduces the number of parts of the regulator to three members which can be snapped together.

What is claimed is: 
     
       1. Apparatus for the I.V. administration of a parenteral liquid to a patient comprising: a. outlet means including an outlet orifice for discharging said parenteral liquid for application to said patient;   b. inlet means for receiving said parenteral liquid;   c. diaphragm means having a flange mounted between said inlet and outlet means and membrane means enclosed by said flange separating incoming parenteral liquid from outgoing parenteral liquid for maintaining the rate of discharge of said parenteral liquid through said outlet orifice;   d. means for bypassing flow of said parenteral liquid from said inlet means to said outlet means around said membrane means;   e. selecting means entirely contained within said apparatus for selecting the rate of flow of said liquid through said apparatus independent of the pressure of parenteral liquid at either the inlet or outlet side of said apparatus; and   f. said membrane means in the absence of liquid flow being shaped in the form of an annular arcuate torus the outer surface of which faces said inlet means, the portion of said membrane means surrounded by said torus forming a bulbous section which is curved outwardly in its resting state in the direction of and controls flow through said outlet orifice, said membrane means in the absence of any liquid in its resting state being unstressed and making no contact with any part of said apparatus thereby remaining unstressed during shipping and storage prior to use and permitting rolling of said torus during flow of liquid through said apparatus as a result of pressure differential across said membrane means so that said bulbous section moves toward and away from said outlet orifice in response to pressure differential across said membrane means.   
     
     
       2. The apparatus of claim 1 having means between said inlet means and said diaphragm means to prevent reversal of flow through said apparatus and delivery of a bolus of said parenteral liquid through said outlet means. 
     
     
       3. The apparatus of claim 2 in which said inlet means has an inlet orifice and said means to prevent delivery of a bolus comprises annular boss means surrounding said inlet orifice extending toward but not contacting said membrane means during normal operation of said apparatus. 
     
     
       4. Apparatus for establishing and maintaining constant the flow rate of liquid passing therethrough comprising: a. inlet and outlet means for receiving and discharging said liquid, respectively;   b. diaphragm means of flexible material mounted between and separating said inlet means from said outlet means including means to permit flow of liquid therethrough;   c. said diaphragm means comprising a membrane unstressed in the absence of liquid surrounded by a flange clamped between said inlet and outlet means, said membrane shaped in the form of an arcuate torus in the unstressed condition the outer surface of which faces said inlet means, the portion of said membrane surrounded by said torus forming a bulbous section the outer surface of which faces said outlet means, said torus and bulbous section being free of contact with any part of said apparatus to permit rolling of said torus;   d. said inlet means having inlet orifice means for discharging said liquid into the region above said diaphragm means;   e. said outlet means having an outlet orifice opposite said bulbous section, said bulbous section regulating the rate of flow through said outlet orifice by moving as a result of rolling of said torus in response to differential liquid pressure across said membrane to maintain constant the flow rate; and   f. means included in said apparatus for selecting the rate of flow of said liquid to be maintained through said apparatus.   
     
     
       5. The apparatus of claim 4 having means to prevent flow reversal therethrough. 
     
     
       6. The apparatus of claim 4 having anti-bolus means to prevent the delivery of a surge of liquid through said outlet means. 
     
     
       7. The apparatus of claim 6 in which said anti-bolus means comprises annular boss means surrounding said inlet orifice means extending toward but not contacting said membrane. 
     
     
       8. The apparatus of claim 7 in which said membrane in the absence of liquid in its resting condition makes no contact with any other part of said apparatus other than said flange being clamped thereby remaining unstressed during shipment and storage. 
     
     
       9. The apparatus of claim 4 in which said flow selecting means adjusts flow of liquid through said diaphragm means. 
     
     
       10. The apparatus of claim 9 in which said flange of said diaphragm means includes a passageway for the flow of said liquid therethrough, means in said outlet means for providing communication between said passageway and the region on the outlet side of said membrane for flow of liquid out through said outlet orifice, and said selecting means including a rotatable means for changing the effective size opening between said passageway and the region on the inlet side of said membrane. 
     
     
       11. The apparatus of claim 10 in which said inlet means and said rotatable means are provided with indicia positioned by rotation of said rotatable means to identify the flow rate to be selected. 
     
     
       12. The apparatus of claim 11 in which is mounted a stationary gasket between said inlet means and said rotatable means having a pair of passageways circumferentially displaced from each other, and said rotatable means is provided with a groove of varying cross section for providing communication between said pair of passageways, the rotation of said rotatable means effectively altering the rate of flow through said apparatus. 
     
     
       13. The apparatus of claim 12 having anti-bolus means to prevent delivery of a surge of liquid through said outlet means comprising annular boss means surrounding said inlet orifice means extending toward but not contacting said membrane. 
     
     
       14. The apparatus of claim 4 in which said membrane in the absence of liquid in its resting condition makes no contact with any other part of said apparatus other than said flange being clamped thereby remaining unstressed during shipment and storage. 
     
     
       15. The apparatus of claim 4 having a drip chamber mounted on said inlet means wherein a reservoir of said liquid is formed with and above said diaphragm. 
     
     
       16. A flow regulator for a liquid comprising: a. rotatable upper housing means containing means to establish a rate of flow through said regulator;   b. stationary lower housing means containing flow inlet means, flow outlet means, and an outlet orifice through which said liquid passes into said flow outlet means; and   c. stationary diaphragm means comprising a membrane surrounded by a flange clamped between said upper and lower housing means, so that both the flow inlet means and the flow outlet means are on the same side of said diaphragm, said membrane shaped in the form of a semi-circular arcuate torus in the unstressed condition the outer surface of which faces said upper housing means, the portion of said membrane surrounded by said torus forming a bulbous section the outer surface of which faces said outlet orifice forming an outlet chamber between said bulbous section and said outlet orifice, an inlet chamber being formed above said bulbous section, said arcuate torus and bulbous section being free of contact with any part of said housing means to permit rolling of said torus;   d. flow means in said diaphragm means for transferring said liquid from said inlet means into said inlet and outlet chambers; and   e. control means in said upper housing means for establishing said rate of flow by selecting the effective opening in said flow means for the transfer of said liquid, said effective opening being obtained by rotation of said upper housing means.   
     
     
       17. The regulator of claim 16 in which said upper housing means includes anti-bolus means to prevent surges of said liquid through said outlet orifice. 
     
     
       18. The regulator of claim 16 in which said flow means includes spaced passageway means in said flange, and said control means includes a tapered groove communicating with both said spaced passageway means, said upper housing being rotatable to adjust the effective opening of said tapered groove exposed to said passageway means.